Optical modules, such as transceiver or transponder modules, are used in telecommunication and data-communication applications to communicate signals between an optical network and a host device, such as a computer, a router, a switch, or a hub. Usually, optical modules are pluggable, meaning that they may be releasably mounted in a cage of the host device. A conventional optical module includes at least one optical subassembly (OSA), such as a transmitter optical subassembly (TOSA) or a receiver optical subassembly (ROSA), and a printed circuit board (PCB) housed within a two-part housing. The optical module also includes a latch mechanism to secure the optical module, once mounted, to the cage of the host device. Examples of conventional optical modules are disclosed in U.S. Pat. No. 6,439,918, issued on Aug. 27, 2002 to Togami, et al., in U.S. Pat. No. 6,994,478, issued on Feb. 7, 2006 to Chiu, et al., in U.S. Pat. No. 7,004,647, issued on Feb. 28, 2006 to Malagrino, Jr., et al., in U.S. Pat. No. 7,114,857, issued on Apr. Oct. 3, 2006 to Kayner, et al., in U.S. Pat. No. 7,118,281, issued on Oct. 10, 2006 to Chiu, et al., in U.S. Pat. No. 7,351,090, issued on Apr. 1, 2008 to Moore, and in U.S. Pat. No. 7,955,003, issued on Jun. 7, 2011 to Teo, et al., which are incorporated herein by reference.
Conventional optical modules incorporate various latch mechanisms, which, typically, include a lever and a latch. Unfortunately, some of these latch mechanisms result in undesirable height limitations. For example, in the latch mechanism disclosed in U.S. Pat. No. 7,351,090, the lever is in the form of a bail including two arms and a handle, and the two arms have bent tabs at ends thereof opposite the handle. The bent tabs, as well as the envelope in the housing required to accommodate the bent tabs, limit how close the OSA can be moved towards the bent tabs. Such height limitations restrict the positioning of the optical axis of the OSA relative to the housing, preventing direct attachment of the OSA to the PCB.
In the manufacture of some conventional optical modules, a covering housing structure is slid horizontally onto a supporting housing structure to assemble the two-part housing. Consequently, a clear sliding path is required, which limits component placement on the PCB. Furthermore, in some conventional optical modules, the OSA is only held in place after the two-part housing is assembled. During assembly and testing, before the two-part housing is assembled, the OSA is free to move and may become misaligned, making insertion of an optical-fiber connector difficult.
As the functional density of optical modules increases, these limitations and shortcomings become increasingly problematic.